Jaundice is a common condition in newborns, and refers to the yellow color of the skin and whites of the eyes caused by an excess of bilirubin in the blood. Bilirubin is produced by the normal breakdown of hemoglobin from red blood cells. Normally, bilirubin is metabolized and conjugated in the liver and is excreted as bile through the intestines. Jaundice occurs when bilirubin levels build up faster than a newborn's liver can break it down and pass it from the body.
Physiological (normal) jaundice occurs in most newborns. This mild jaundice is due to the immaturity of the baby's liver, which leads to a slow processing of bilirubin. It generally appears at 2 to 4 days of age and disappears by 1 to 2 weeks of age, and does not need treatment. Breastfeeding jaundice can occur when a breastfeeding baby is not getting enough breast milk because of difficulty with breastfeeding or because the mother's milk isn't in yet. This is not caused by a problem with the breast milk itself, but by the baby not getting enough to drink. Breastfeeding jaundice also appears in the first few days of life. Jaundice of prematurity occurs frequently in premature babies since they are even less ready to excrete bilirubin effectively. Jaundice in premature babies needs to be treated at a lower bilirubin level than in full term babies in order to avoid complications.
Pathologic (abnormal) jaundice can lead to a faster and higher rise of bilirubin levels. Causes of pathologic jaundice are many. Increased hemolysis, from ABO blood type incompatibilities, RBC membrane defects, and RBC enzyme defects, resolving cephaihematomas, maternal-fetal transfusion, and sepsis can result in high bilirubin levels. Pathologic jaundice can also result from a defect in the newborn liver preventing proper conjugation and excretion. Examples of this are decreased enzyme activity with prematurity, breast milk jaundice, hypothyroidism, and metabolic diseases. Finally, impaired excretion can occur from TORCH infections, severe metabolic disease, and hepato-biliary atresia, and can result in extremely high levels of bilirubin.
High levels of bilirubin—usually above 25 mg—can cause deafness, cerebral palsy, or other forms of brain damage in some babies, a condition called kernicterus. Because of this, the American Academy of Pediatrics recommends that all infants should be examined for jaundice within a few days of birth. Evaluation is done by simple blood test or, more recently, a transcutaneous bilirubin test device. If elevated bilirubin levels are found, they are plotted on a graph which correlates the infant's age (in hours) to the bilirubin level to determine the severity of the condition. When bilirubin levels are found to be in the range that warrants concern, treatment is begun.
The mainstay of treatment of hyperbilirubinemia is phototherapy. Phototherapy exposes the jaundiced infant to a bright blue-white light that creates bilirubin photoisomers in the skin of the patient. Normally, un-conjugated bilirubin is poorly water soluble and is mostly excreted through the bile, with only a small amount being excreted into the urine. Photo-isomerized bilirubin, however, is much more water soluble, and is readily excreted by the kidneys into the urine.
The efficacy of phototherapy relies on a combination of intensity and duration. Since only the skin under the phototherapy light can contribute to the photoisomerism, it is important that the child be as undressed as possible during the procedure. This usually translates into only diapers (for hygiene) and eye-shields (for safety).
A problem is that many infants, particularly premature infants also receiving other treatments such as nasal CPAP, are often restless during the phototherapy process and do not lay still. This causes undue stress on the infant, and can lead to increase respiratory and heart rates, increase energy expenditure, over-heating, and discomfort. A simple technique used in the nursery to calm irritable infants is swaddling, which is a method of snugly wrapping the infant in a blanket. The snug wrap comforts and quiets the infant without the need for medication. However, swaddling is not currently an option in infants undergoing a course of phototherapy because the blankets currently used would block most or all of the phototherapy light from reaching the infant's skin, rendering the phototherapy procedure ineffective.
Larsson, et al (U.S. Pat. No. 6,253,380) describes a restraining garment for an infant receiving phototherapy, said garment being comprised of a generally rectangular blanket with a pouch sized to receive an infant being disposed on its surface, and having a bottom surface substantially transparent to phototherapy light. In practice, the infant is placed in the pouch, and the entire garment placed over a phototherapy lamp. The infant thus receives phototherapy by illumination from below through the substantially transparent garment. There are significant problems with this approach. First, phototherapy lamps commonly available and in use in most nurseries are designed to rest above the infant and deliver illumination from above. There is no practical way to alter or re-configure these lights to provide illumination from below the infant, thus the device disclosed by Larrson would require the use of a new and specifically designed phototherapy lamp. Second, the garment described by Larrson discloses a simple pouch for holding the infant, with additional arms in said pouch for receiving the arms of the infant. Although this would be sufficient to restrain the infant's movement, such a garment would not provide the snug restraint needed for swaddling and thus would do little or nothing to comfort an infant undergoing a course of phototherapy for hyperbilirubinemia.
Rice (US 2008/0116401) discloses a method and apparatus for stabilizing a subject undergoing phototherapy treatment. In her patent application, Rice discloses a garment that is substantially transparent to phototherapy light and a method wherein an infant requiring phototherapy for hyperbilirubinemia is wrapped or clothed in said garment prior to the delivery of phototherapy. It is understood that the garment described in the Rice application may take several forms, including a blanket, a hat, or other suitable garment.
The Rice application does not specifically refer to the use of a blanket-like garment for swaddling and thereby comforting an infant receiving phototherapy. However, one skilled in the art will realize that the square or rectangular blanket in the Rice application can be used for such purpose. A problem, however, with the use of a simple square or rectangular blanket for swaddling an infant is that it will necessarily require the blanket to be wrapped more than once around the infant to provide a tight and securely snug wrap. This will result in at least two and perhaps multiple layers of fabric lying between the phototherapy lamp and the infant's skin. Unless the fabric material used in the construction of the garment disclosed by Rice is 100% transparent to the phototherapy light, each layer of fabric interposed between the infant and the phototherapy lamp will diminish the intensity of the phototherapy energy and reduce the effectiveness of the treatment. Multiple layers of fabric could potentially degrade the phototherapy energy to the point where the treatment is unduly prolonged or becomes ineffectual. No mention is made in the Rice application as to how to remedy this problem.
There are multiple patents describing blankets intended to swaddle an infant. Representative of these designs are those disclosed by Gatten (U.S. Pat. No. 7,181,789; U.S. Pat. No. 7,043,783; and U.S. Pat. No. 6,868,566). Gatten discloses an infant swaddling blanket formed from a continuous piece of material and having two arms. One blanket arm is just long enough to wrap once over an infant and be tucked partially beneath the infant. The other blanket arm extends from the opposite side of the back panel and is long enough to wrap around the infant more than once. It is recognized that a swaddling blanket of this construction would intersperse multiple layers of material between the infant and the phototherapy light and would significantly degrade the efficacy of the phototherapy treatment, possibly rendering it ineffectual. Thus, a swaddling blanket as disclosed by Gatten could not be used for swaddling an infant receiving phototherapy.